Blocklist D3D12 adapters on ARM CPUs

This platform still has undiagnosed errors. Blocklisting for V1.

Bug: dawn:884
Change-Id: I83c51f48732ace5c3c4b16ee9906af0d8a3cccdb
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/120080
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Kokoro: Kokoro <noreply+kokoro@google.com>
Commit-Queue: Austin Eng <enga@chromium.org>

src/dawn/native/d3d12/AdapterD3D12.cpp

@@ -108,6 +108,9 @@ MaybeError Adapter::InitializeImpl() {
         DAWN_INVALID_IF(
             gpu_info::IsNvidia(mVendorId),
             "D3D12 NVIDIA x86 adapter is blocklisted. See https://crbug.com/dawn/1196.");
+#elif DAWN_PLATFORM_IS(ARM)
+        return DAWN_VALIDATION_ERROR(
+            "D3D12 on ARM CPU is blocklisted. See https://crbug.com/dawn/884.");
 #endif
     }
     return {};